// Copyright (c) 2011-2016 The Bitcoin Core developers
// Copyright (c) @2024 The PHICOIN Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "policy/policy.h"
#include "policy/fees.h"
#include "txmempool.h"
#include "uint256.h"
#include "util.h"

#include "test/test_phicoin.h"

#include <boost/test/unit_test.hpp>

BOOST_FIXTURE_TEST_SUITE(policyestimator_tests, BasicTestingSetup)

    BOOST_AUTO_TEST_CASE(block_policy_estimates_test)
    {
        BOOST_TEST_MESSAGE("Running Block Policy Estimates Test");

        CBlockPolicyEstimator feeEst;
        CTxMemPool mpool(&feeEst);
        TestMemPoolEntryHelper entry;
        CAmount basefee(2000);
        CAmount deltaFee(100);
        std::vector<CAmount> feeV;

        // Populate vectors of increasing fees
        for (int j = 0; j < 10; j++)
        {
            feeV.push_back(basefee * (j + 1));
        }

        // Store the hashes of transactions that have been
        // added to the mempool by their associate fee
        // txHashes[j] is populated with transactions either of
        // fee = basefee * (j+1)
        std::vector<uint256> txHashes[10];

        // Create a transaction template
        CScript garbage;
        for (unsigned int i = 0; i < 128; i++)
            garbage.push_back('X');
        CMutableTransaction tx;
        tx.vin.resize(1);
        tx.vin[0].scriptSig = garbage;
        tx.vout.resize(1);
        tx.vout[0].nValue = 0LL;
        CFeeRate baseRate(basefee, GetVirtualTransactionSize(tx));

        // Create a fake block
        std::vector<CTransactionRef> block;
        int blocknum = 0;

        // Loop through 200 blocks
        // At a decay .9952 and 4 fee transactions per block
        // This makes the tx count about 2.5 per bucket, well above the 0.1 threshold
        while (blocknum < 200)
        {
            for (int j = 0; j < 10; j++)
            { // For each fee
                for (int k = 0; k < 4; k++)
                { // add 4 fee txs
                    tx.vin[0].prevout.n = 10000 * blocknum + 100 * j + k; // make transaction unique
                    uint256 hash = tx.GetHash();
                    mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Height(blocknum).FromTx(tx));
                    txHashes[j].push_back(hash);
                }
            }
            //Create blocks where higher fee txs are included more often
            for (int h = 0; h <= blocknum % 10; h++)
            {
                // 10/10 blocks add highest fee transactions
                // 9/10 blocks add 2nd highest and so on until ...
                // 1/10 blocks add lowest fee transactions
                while (txHashes[9 - h].size())
                {
                    CTransactionRef ptx = mpool.get(txHashes[9 - h].back());
                    if (ptx)
                        block.push_back(ptx);
                    txHashes[9 - h].pop_back();
                }
            }
            mpool.removeForBlock(block, ++blocknum);
            block.clear();
            // Check after just a few txs that combining buckets works as expected
            if (blocknum == 3)
            {
                // At this point we should need to combine 3 buckets to get enough data points
                // So estimateFee(1) should fail and estimateFee(2) should return somewhere around
                // 9*baserate.  estimateFee(2) %'s are 100,100,90 = average 97%
                BOOST_CHECK(feeEst.estimateFee(1) == CFeeRate(0));
                BOOST_CHECK(feeEst.estimateFee(2).GetFeePerK() < 9 * baseRate.GetFeePerK() + deltaFee);
                BOOST_CHECK(feeEst.estimateFee(2).GetFeePerK() > 9 * baseRate.GetFeePerK() - deltaFee);
            }
        }

        std::vector<CAmount> origFeeEst;
        // Highest feerate is 10*baseRate and gets in all blocks,
        // second highest feerate is 9*baseRate and gets in 9/10 blocks = 90%,
        // third highest feerate is 8*base rate, and gets in 8/10 blocks = 80%,
        // so estimateFee(1) would return 10*baseRate but is hardcoded to return failure
        // Second highest feerate has 100% chance of being included by 2 blocks,
        // so estimateFee(2) should return 9*baseRate etc...
        for (int i = 1; i < 10; i++)
        {
            origFeeEst.push_back(feeEst.estimateFee(i).GetFeePerK());
            if (i > 2)
            { // Fee estimates should be monotonically decreasing
                BOOST_CHECK(origFeeEst[i - 1] <= origFeeEst[i - 2]);
            }
            int mult = 11 - i;
            if (i % 2 == 0)
            { //At scale 2, test logic is only correct for even targets
                BOOST_CHECK(origFeeEst[i - 1] < mult * baseRate.GetFeePerK() + deltaFee);
                BOOST_CHECK(origFeeEst[i - 1] > mult * baseRate.GetFeePerK() - deltaFee);
            }
        }
        // Fill out rest of the original estimates
        for (int i = 10; i <= 48; i++)
        {
            origFeeEst.push_back(feeEst.estimateFee(i).GetFeePerK());
        }

        // Mine 50 more blocks with no transactions happening, estimates shouldn't change
        // We haven't decayed the moving average enough so we still have enough data points in every bucket
        while (blocknum < 250)
            mpool.removeForBlock(block, ++blocknum);

        BOOST_CHECK(feeEst.estimateFee(1) == CFeeRate(0));
        for (int i = 2; i < 10; i++)
        {
            BOOST_CHECK(feeEst.estimateFee(i).GetFeePerK() < origFeeEst[i - 1] + deltaFee);
            BOOST_CHECK(feeEst.estimateFee(i).GetFeePerK() > origFeeEst[i - 1] - deltaFee);
        }


        // Mine 15 more blocks with lots of transactions happening and not getting mined
        // Estimates should go up
        while (blocknum < 265)
        {
            for (int j = 0; j < 10; j++)
            { // For each fee multiple
                for (int k = 0; k < 4; k++)
                { // add 4 fee txs
                    tx.vin[0].prevout.n = 10000 * blocknum + 100 * j + k;
                    uint256 hash = tx.GetHash();
                    mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Height(blocknum).FromTx(tx));
                    txHashes[j].push_back(hash);
                }
            }
            mpool.removeForBlock(block, ++blocknum);
        }

        for (int i = 1; i < 10; i++)
        {
            BOOST_CHECK(feeEst.estimateFee(i) == CFeeRate(0) || feeEst.estimateFee(i).GetFeePerK() > origFeeEst[i - 1] - deltaFee);
        }

        // Mine all those transactions
        // Estimates should still not be below original
        for (int j = 0; j < 10; j++)
        {
            while (txHashes[j].size())
            {
                CTransactionRef ptx = mpool.get(txHashes[j].back());
                if (ptx)
                    block.push_back(ptx);
                txHashes[j].pop_back();
            }
        }
        mpool.removeForBlock(block, 266);
        block.clear();
        BOOST_CHECK(feeEst.estimateFee(1) == CFeeRate(0));
        for (int i = 2; i < 10; i++)
        {
            BOOST_CHECK(feeEst.estimateFee(i) == CFeeRate(0) || feeEst.estimateFee(i).GetFeePerK() > origFeeEst[i - 1] - deltaFee);
        }

        // Mine 400 more blocks where everything is mined every block
        // Estimates should be below original estimates
        while (blocknum < 665)
        {
            for (int j = 0; j < 10; j++)
            { // For each fee multiple
                for (int k = 0; k < 4; k++)
                { // add 4 fee txs
                    tx.vin[0].prevout.n = 10000 * blocknum + 100 * j + k;
                    uint256 hash = tx.GetHash();
                    mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Height(blocknum).FromTx(tx));
                    CTransactionRef ptx = mpool.get(hash);
                    if (ptx)
                        block.push_back(ptx);

                }
            }
            mpool.removeForBlock(block, ++blocknum);
            block.clear();
        }
        BOOST_CHECK(feeEst.estimateFee(1) == CFeeRate(0));
        for (int i = 2; i < 9; i++)
        { // At 9, the original estimate was already at the bottom (b/c scale = 2)
            BOOST_CHECK(feeEst.estimateFee(i).GetFeePerK() < origFeeEst[i - 1] - deltaFee);
        }
    }

BOOST_AUTO_TEST_SUITE_END()
